I have a 30-meter raster that represents 10 land areas of different sizes. Each of these areas is composed of a variety of surface materials.. e.g. grass, cement, pavement, dirt, trees etc in different proportions. I know the proportions which these surface materials occur within each area, but I don't know the exact spatial location of the materials.. so, what I would like to do is create another raster layer that randomly distributes the surface material within each of the 10 land areas.

I am using ArcGIS 10.3 for Desktop.

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    Please don't sign your posts because your user card already does that. This is covered in the help center that leads on from the Tour that I noticed you have not yet taken. – PolyGeo Oct 30 '15 at 5:55
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    Random raster first. Class by class afterwards, by converting percentage of grass into raster. Grass=con (random <raster,1). Next classes use con and previous class – FelixIP Oct 30 '15 at 6:34
  • I think questions is not very clear. You need to elaborate it. Do you require it to be totally random? Geography is not that random. Do you want certain type of lands to be closer to each other? Total randomness would create something that is absolutely useless. – Celik A Oct 30 '15 at 8:13
  • Whether or not it's useless, could you please tell me how to do it? Each of the 'land areas' which are ownership areas are contiguous. I have a separate non-spatial proportion of coverage values, I need to put these proportions in before running a separate model that predicts the Albedo, so it doesn't matter in particular where the cover is, but it should be evenly distributed across the sections and the more random the better. – Jim Richalds Oct 30 '15 at 10:50

FelixIP answered the question.

Make a random raster that covers the extent of all 10 areas. For each area extract the values of the random raster to a new raster using extract by mask. Reclassify the resulting clipped random raster based on your knowledge of percentages for that areas. For example, if area 1 is 20% grass then all values <=.2 reclassify to 1, for 5%pavement then >.2 to .25 become 2...

Repeat for the other 9 areas.

Mosaic the resulting 10 reclassified rasters back together.


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